Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines generally comprise a rotor with a rotor hub and a plurality of blades. The rotor is set into rotation under the influence of the wind on the blades. The rotation of a rotor shaft drives a generator rotor either directly (“directly driven”) or through the use of a gearbox. The gearbox (if present), the generator and other systems are usually mounted in a nacelle on top of a wind turbine tower.
The size/length of wind turbine blades is continuously increasing with the aim of maximizing the capture of kinetic energy from the wind and, therefore, generating larger amounts of electrical energy. The increasing size of the blades may make the transportation of the blades more complex and expensive. Road transportation of very long blades may require considerably long vehicles and trailers, and maritime transportation of enormous blades may similarly require large ships and barges.
It is known that blades may be constructed according to a modular approach, such that different modules or parts of the blade may be transported separately and therefore more cheaply.
However, having a blade composed of separate parts to be coupled to each other (to form the final blade) may require said blade parts to be made of larger amounts of material to ensure acceptable structural stiffness and resistance. In other words, the division of the blade in different parts may negatively affect the structural stiffness and resistance of the final blade. This is normally attenuated or compensated by manufacturing certain blade parts thicker and therefore heavier (i.e. with larger amounts of material) especially around their coupling regions.
Moreover, increased amounts of extra fastening material, which may add considerable extra weight to the final blade, may also be needed for suitably coupling the (thicker and heavier) blade parts together. The increase in additional fastening material (e.g. flanges, screws, bolts, welding, etc.) may be necessary in order to ensure that the final blade is structurally able to withstand all loads.
It is known that, in some particular examples of modular blades, approximately one tonne or more than one tonne of extra weight may be added over a total weight of about fifteen tonnes for the entire/final blade.
It is an object of the present disclosure to provide wind turbine blade modules, systems for transporting said blade modules, and methods of assembling said blade modules to form wind turbine blades that at least partially reduce one or more of the aforementioned drawbacks.